<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>hover</title>
    <style>
        img{
            width: 100px;
            height: 100px;
            /* 透明度[0.0,1.0] */
            opacity: 0.4;
        }
    
        img:hover{
            opacity: 1;
            width: 150px;
            height: 150px;
        }
    </style>
</head>
<body>
    <div>
        <img src="../../part01-html/imgs/xx.png" alt="">
        <img src="../../part01-html/imgs/xx.png" alt="">
        <img src="../../part01-html/imgs/xx.png" alt="">
    </div>
</body>
</html>